Microglial and Astrocytic Responses in the Human Midcingulate Cortex in Huntington's Disease.

OBJECTIVE: Patients with Huntington's disease can present with variable difficulties of motor functioning, mood, and cognition. Neurodegeneration occurs in the anterior cingulate cortex of some patients with Huntington's disease and is linked to the presentation of mood symptomatology. Neuroinflammation, perpetrated by activated microglia and astrocytes, has been reported in Huntington's disease and may contribute to disease progression and presentation. This study sought to quantify the density of mutant huntingtin protein and neuroinflammatory glial changes in the midcingulate cortex of postmortem patients with Huntington's disease and determine if either correlates with the presentation of mood, motor, or mixed symptomatology. METHODS: Free-floating immunohistochemistry quantified 1C2 immunolabeling density as an indicative marker of mutant huntingtin protein, and protein and morphological markers of astrocyte (EAAT2, Cx43, and GFAP), and microglial (Iba1 and HLA-DP/DQ/DR) activation. Relationships among the level of microglial activation, mutant huntingtin burden, and case characteristics were explored using correlative analysis. RESULTS: We report alterations in activated microglia number and morphology in the midcingulate cortex of Huntington's disease cases with predominant mood symptomatology. An increased proportion of activated microglia was observed in the midcingulate of all Huntington's disease cases and positively correlated with 1C2 burden. Alterations in the astrocytic glutamate transporter EAAT2 were observed in the midcingulate cortex of patients associated with mood symptoms. INTERPRETATION: This study presents pathological changes in microglia and astrocytes in the midcingulate cortex in Huntington's disease, which coincide with mood symptom presentation. These findings further the understanding of neuroinflammation in Huntington's disease, a necessary step for developing inflammation-targeted therapeutics. ANN NEUROL 2023;94:895-910.

Do men who have sex with men recognise syphilis symptoms? A syphilis awareness campaign in Amsterdam, the Netherlands.

INTRODUCTION: Syphilis incidence is rising among gay, bisexual and other men who have sex with men (GBMSM). To improve early health-seeking behaviour, we developed an online syphilis symptom score tool for GBMSM to self-identify a higher likelihood of infectious syphilis and promoted its use via an online and offline awareness campaign. METHODS: From October 2018 through September 2019, a dedicated website on syphilis including the online symptom score tool was promoted. The reach of the campaign was measured by website metrics and the completion of the self-assessment tool. The impact of the campaign was assessed by comparing the monthly number of syphilis serology tests and the percentages of infectious syphilis diagnoses at the Centre for Sexual Health (CSH) in Amsterdam between three periods: 12 months preceding, 12 months during and 6 months after the campaign. RESULTS: During the campaign, 20 341 visitors viewed the website. A total of 13 499 (66.4%) visitors started the self-assessment algorithm, and 11 626 (86.1%) completed it. Prior to the campaign, the mean number of syphilis tests per month was 1650 compared with 1806 per month during the campaign (p=0.02). In the 6 months after the campaign, the mean number of tests per month was 1798 (compared with the period of the campaign, p=0.94). Prior to the campaign, the percentage of infectious syphilis diagnoses was 2.5% compared with 3.0% during the campaign (p=0.009). The percentage of infectious syphilis diagnoses in the 6 months after the campaign was 2.2% (p<0.0001 compared with the period of the campaign, and p=0.045, compared with the period prior to the campaign). CONCLUSIONS: Although we did not find definite proof of a (sustained) effect, syphilis symptoms awareness campaigns deserve further evaluation and improvements to help those suspected of syphilis to get tested.

Spatial dynamics of malaria transmission.

The Ross-Macdonald model has exerted enormous influence over the study of malaria transmission dynamics and control, but it lacked features to describe parasite dispersal, travel, and other important aspects of heterogeneous transmission. Here, we present a patch-based differential equation modeling framework that extends the Ross-Macdonald model with sufficient skill and complexity to support planning, monitoring and evaluation for Plasmodium falciparum malaria control. We designed a generic interface for building structured, spatial models of malaria transmission based on a new algorithm for mosquito blood feeding. We developed new algorithms to simulate adult mosquito demography, dispersal, and egg laying in response to resource availability. The core dynamical components describing mosquito ecology and malaria transmission were decomposed, redesigned and reassembled into a modular framework. Structural elements in the framework-human population strata, patches, and aquatic habitats-interact through a flexible design that facilitates construction of ensembles of models with scalable complexity to support robust analytics for malaria policy and adaptive malaria control. We propose updated definitions for the human biting rate and entomological inoculation rates. We present new formulas to describe parasite dispersal and spatial dynamics under steady state conditions, including the human biting rates, parasite dispersal, the "vectorial capacity matrix," a human transmitting capacity distribution matrix, and threshold conditions. An [Formula: see text] package that implements the framework, solves the differential equations, and computes spatial metrics for models developed in this framework has been developed. Development of the model and metrics have focused on malaria, but since the framework is modular, the same ideas and software can be applied to other mosquito-borne pathogen systems.

Comparing metapopulation dynamics of infectious diseases under different models of human movement.

Newly available datasets present exciting opportunities to investigate how human population movement contributes to the spread of infectious diseases across large geographical distances. It is now possible to construct realistic models of infectious disease dynamics for the purposes of understanding global-scale epidemics. Nevertheless, a remaining unanswered question is how best to leverage the new data to parameterize models of movement, and whether one's choice of movement model impacts modeled disease outcomes. We adapt three well-studied models of infectious disease dynamics, the susceptible-infected-recovered model, the susceptible-infected-susceptible model, and the Ross-Macdonald model, to incorporate either of two candidate movement models. We describe the effect that the choice of movement model has on each disease model's results, finding that in all cases, there are parameter regimes where choosing one movement model instead of another has a profound impact on epidemiological outcomes. We further demonstrate the importance of choosing an appropriate movement model using the applied case of malaria transmission and importation on Bioko Island, Equatorial Guinea, finding that one model produces intelligible predictions of R0, whereas the other produces nonsensical results.

Developing a symptoms-based risk score for infectious syphilis among men who have sex with men.

BACKGROUND: Syphilis incidence is rising among men who have sex with men (MSM). An online tool based on a risk score identifying men with higher risk of infectious syphilis could motivate MSM to seek care. We aimed therefore to develop a symptoms-based risk score for infectious syphilis. METHODS: We included data from all consultations by MSM attending the Amsterdam Centre for Sexual Health in 2018-2019. Infectious syphilis (ie, primary, secondary or early latent syphilis) was diagnosed according to the centre's routine protocol. Associations between symptoms and infectious syphilis were expressed as odds ratios (OR), with 95% confidence intervals (CI). Based on multivariable logistic regression models, we created risk scores, combining various symptoms. We assessed the area under the curve (AUC) and cut-off based on the Youden Index. We estimated which percentage of MSM should be tested based on a positive risk score and which percentage of infectious syphilis cases would then be missed. RESULTS: We included 21,646 consultations with 11,594 unique persons. The median age was 34 years (IQR 27-45), and 14% were HIV positive (93% on antiretroviral treatment). We diagnosed 538 cases of infectious syphilis. Associations with syphilis symptoms/signs were strong and highly significant, for example, OR for a painless penile ulcer was 35.0 (CI 24.9 to 49.2) and OR for non-itching rash 57.8 (CI 36.8 to 90.9). Yet, none of the individual symptoms or signs had an AUC >0.55. The AUC of risk scores combining various symptoms varied from 0.68 to 0.69. For all risk scores using cut-offs based on Youden Index, syphilis screening would be recommended in 6% of MSM, and 59% of infectious syphilis cases would be missed. CONCLUSION: Symptoms-based risk scores for infectious syphilis perform poorly and cannot be recommended to select MSM for syphilis screening. All MSM with relevant sexual exposure should be regularly tested for syphilis.

Co-producing Human and Animal Experimental Subjects: Exploring the Views of UK COVID-19 Vaccine Trial Participants on Animal Testing.

Preclinical (animal) testing and human testing of drugs and vaccines are rarely considered by social scientists side by side. Where this is done, it is typically for theoretically exploring the ethics of the two situations to compare relative treatment. In contrast, we empirically explore how human clinical trial participants understand the role of animal test subjects in vaccine development. Furthermore, social science research has only concentrated on broad public opinion and the views of patients about animal research, whereas we explore the views of a public group particularly implicated in pharmaceutical development: experimental subjects. We surveyed and interviewed COVID-19 vaccine trial participants in Oxford, UK, on their views about taking part in a vaccine trial and the role of animals in trials. We found that trial participants mirrored assumptions about legitimate reasons for animal testing embedded in regulation and provided insight into (i) the nuances of public opinion on animal research; (ii) the co-production of human and animal experimental subjects; (iii) how vaccine and medicine testing, and the motivations and demographics of clinical trial participants, change in an outbreak; and (iv) what public involvement can offer to science.

Therapeutic games to reduce anxiety and depression in young people: A systematic review and exploratory meta-analysis of their use and effectiveness.

OBJECTIVE: The development of serious games for mental wellbeing is a topic of growing interest. The increase in acceptance of games as a mainstream entertainment medium combined with the immersive qualities of games provides opportunities for meaningful support and intervention in mental wellbeing. METHOD: We conducted a systematic review and exploratory meta-analysis to examine if aspects of the interventions influenced outcomes as measured via overall effect sizes. We employed a multilevel meta-analytic approach to accommodate the interdependency of effect sizes (18 effect sizes from 14 studies, with 2027 participants). RESULTS: Overall, the main effect for gaming interventions on any outcome variable was small to medium sized, d = .35 (confidence interval [.23, 47], p < .001). Results revealed that the only significant moderator was the nature of the intervention. Specifically, only interventions that included a rational emotional behavioural focus significantly predicted an improvement in depression and/or anxiety in participants. CONCLUSION: The findings reveal promising effects for therapeutic games for mental health, but replications are needed, alongside the addressing of methodological and procedural concerns.

Newton's 'De Aere et Aethere' and the introduction of interparticulate forces into his physics.

As well as the mathematically-supported celestial mechanics that Newton developed in his Principia, Newton also proposed a more speculative natural philosophy of interparticulate forces of attraction and repulsion. Although this speculative philosophy was not made public before the 'Queries' which Newton appended to the Opticks, it originated far earlier in Newton's career. This article makes the case that Newton's short, unfinished manuscript, entitled 'De Aere et Aethere', should be seen as an important landmark in Newton's intellectual development, being the first work in which Newton assumed there are repulsive forces operating at a distance between the particles of bodies. The article offers an account of how Newton came to write 'De Aere et Aethere' and why. It also outlines its relationship to the 'Conclusio', with which Newton briefly intended to finish the Principia, and to the 'Queries' in the Opticks. The date of the manuscript is disputed, and the article also aims to settle this dispute. Claims that the 'De Aere et Aethere' must have been written before the 'Hypothesis... of Light' of 1675 are dismissed, and it is suggested, following R. S. Westfall, that it was written after a well-known letter Newton wrote to Boyle early in 1679.

Clinical outcomes of syphilis in HIV-negative and HIV-positive MSM: occurrence of repeat syphilis episodes and non-treponemal serology responses.

OBJECTIVES: HIV-positive men who have sex with men (MSM) may be at a higher risk of repeat syphilis, have different clinical manifestations and have a different serological response to treatment compared with HIV-negative MSM. The objective of this study was to assess whether HIV-negative and HIV-positive MSM with infectious syphilis (primary, secondary or early latent) differed in history of previous syphilis episodes, disease stage and non-treponemal titre of initial and repeat episodes, and the titre response 6 and 12 months after treatment. Furthermore, determinants associated with an inadequate titre response after treatment were explored. METHODS: This retrospective analysis used data of five longitudinal studies (four cohorts; one randomised controlled trial) conducted at the STI clinic in Amsterdam, the Netherlands. Participants were tested for syphilis and completed questionnaires on sexual risk behaviour every 3-6 months. We included data of participants with ≥1 syphilis diagnosis in 2014-2019. Pearson's χ² test was used to compare HIV-negative and HIV-positive MSM in occurrence of previous syphilis episodes, disease stage of initial and repeat syphilis episode and non-treponemal titre treatment responses. RESULTS: We included 355 participants with total 459 syphilis episodes. HIV-positive MSM were more likely to have a history of previous syphilis episodes compared with HIV-negative MSM (68/90 (75.6%) vs 96/265 (36.2%); p<0.001). Moreover, HIV-positive MSM with repeat syphilis were less often diagnosed with primary syphilis (7/73 (9.6%) vs 36/126 (28.6%)) and more often diagnosed with secondary syphilis (16/73 (21.9%) vs 17/126 (13.5%)) and early latent syphilis (50/73 (68.5%) vs 73/126 (57.9%)) (p=0.005). While not significantly different at 12 months, HIV-negative MSM were more likely to have an adequate titre response after 6 months compared with HIV-positive MSM (138/143 (96.5%) vs 66/74 (89.2%); p=0.032). CONCLUSIONS: In repeat syphilis, HIV infection is associated with advanced syphilis stages and with higher non-treponemal titres. HIV infection affects the serological outcome after treatment, as an adequate titre response was observed earlier in HIV-negative MSM.

Barriers and Motives for Complying With "Sexual Distancing" Among Men Who Have Sex With Men During the First COVID-19 Pandemic Lockdown in Amsterdam: A Qualitative Study.

BACKGROUND: Between March 15 and May 31, 2020, the Dutch government imposed lockdown and health measures to curb the coronavirus disease 2019 (COVID-19) pandemic. As part of social distancing, sexual distancing was one of these measures. Sexual distancing implied refraining from sex with partners outside of one's household. We aimed to elucidate barriers and motives for complying with sexual distancing and related factors that could have led to (non)compliance among men who have sex with men. METHODS: In this exploratory qualitative study, we interviewed men who have sex with men who visited the center for sexual health in Amsterdam during the first COVID-19 lockdown using a semistructured interview guide from March to May 2020. We interviewed both men who complied and did not comply with sexual distancing. The interviews were transcribed verbatim and analyzed using an open-coding process in MAXQDA. RESULTS: We included 18 noncompliers and 4 compliers to COVID-19 sexual distancing. Barriers to compliance were the following: lack of information on, or understanding of, the need for sexual distancing; being single; having had an active sex life before COVID-19; a high perceived importance of the social aspect of sex; a strong urge for sex; using sex to cope with the negative impact of the pandemic; being under the influence of alcohol or drugs; and not perceiving COVID-19 as a serious health threat. Motives for compliance were the following: perceiving COVID-19 as a serious health threat, direct confrontation with critically ill COVID-19 patients, protecting someone dear from COVID-19, and being convinced of the importance of social and/or sexual distancing measures. CONCLUSIONS: Information on sexual distancing needs to be made more explicit, accessible, understandable, inclusive, customized to individual barriers, and relatable to the key populations. This may improve the effectiveness of measures and health recommendations in both the current COVID-19 pandemic and future respiratory outbreaks.

Infection age as a predictor of epidemiological metrics for malaria.

BACKGROUND: Accurate estimation of the burden of Plasmodium falciparum is essential for strategic planning for control and elimination. Due in part to the extreme heterogeneity in malaria exposure, immunity, other causes of disease, direct measurements of fever and disease attributable to malaria can be difficult. This can make a comparison of epidemiological metrics both within and between populations hard to interpret. An essential part of untangling this is an understanding of the complex time-course of malaria infections. METHODS: Historic data from malariatherapy infections, in which individuals were intentionally infected with malaria parasites, were reexamined in aggregate. In this analysis, the age of each infection was examined as a potential predictor describing aggregate patterns across all infections. A series of piecewise linear and generalized linear regressions were performed to highlight the infection age-dependent patterns in both parasitaemia and gametocytaemia, and from parasitaemia and gametocytaemia to fever and transmission probabilities, respectively. RESULTS: The observed duration of untreated patent infection was 130 days. As infections progressed, the fraction of infections subpatent by microscopy was seen to increase steadily. The time-averaged malaria infections had three distinct phases in parasitaemia: a growth phase for the first 6 days of patency, a rapid decline from day 6 to day 18, and a slowly declining chronic phase for the remaining duration of the infection. During the growth phase, parasite densities increased sharply to a peak. Densities sharply decline for a short period of time after the peak. During the chronic phase, infections declined steadily as infections age. gametocytaemia was strongly correlated with lagged asexual parasitaemia. Fever rates and transmission efficiency were strongly correlated with parasitaemia and gametocytaemia. The comparison between raw data and prediction from the age of infection has good qualitative agreement across all quantities of interest for predicting averaged effects. CONCLUSION: The age of infection was established as a potentially useful covariate for malaria epidemiology. Infection age can be estimated given a history of exposure, and accounting for exposure history may potentially provide a new way to estimate malaria-attributable fever rates, transmission efficiency, and patent fraction in immunologically naïve individuals such as children and people in low-transmission regions. These data were collected from American adults with neurosyphilis, so there are reasons to be cautious about extending the quantitative results reported here to general populations in malaria-endemic regions. Understanding how immune responses modify these statistical relationships given past exposure is key for being able to apply these results more broadly.

Quality of life of cutaneous leishmaniasis suspected patients in the Ecuadorian Pacific and Amazon regions: a cross sectional study.

BACKGROUND: Yearly, up to 1 million patients worldwide suffer from cutaneous leishmaniasis (CL). In Ecuador, CL affects an estimated 5000 patients annually. CL leads to reduced Health Related Quality of Life (HRQL) as a result of stigma in the Asian and Mediterranean contexts, but research is lacking for Ecuador. The objective of this study was to explore the influence of CL suspected lesions on the quality of life of patients in the Pacific and Amazon regions. METHODS: Patients for this study were included in the Amazonian Napo, Pastaza, and Morona Santiago provinces and the Pacific region of the Pichincha province. Participating centers offered free of charge CL treatment. All patients suspected of CL and referred for a cutaneous smear slide microscopy examination were eligible. This study applied the Skindex-29 questionnaire, a generic tool to measure HRQL in patients with skin diseases. All statistical analysis was done with SPSS Statistics version 28. RESULTS: The skindex-29 questionnaire was completed adequately by 279 patients who were included in this study. All patient groups from the Amazon scored significantly (P < 0.01) higher (indicating worse HRQL) on all the dimensions of the Skindex-29 questionnaire than Mestizo patients from the Pacific region. The percentage of patients with health seeking delay of less than a month was significantly (P < 0.01) lower in the Amazon region (38%) than in the Pacific (66%). CONCLUSIONS: The present study revealed that the influence of suspected CL lesions on the HRQL of patients in the Ecuadorian Amazon and Pacific depends on the geographic region more than on patient characteristics such as gender, age, number of lesions, lesion type, location of lesions, health seeking delay, or posterior confirmation of the Leishmania parasite. The health seeking delay in the Amazon might result from a lack of health infrastructure or related stigma. Together, the impaired HRQL and prolonged health seeking delay in the Amazon lead to prolonged suffering and a worse health outcome. Determinants of health seeking delay should be clarified in future studies and CL case finding must be improved. Moreover, HRQL analysis in other CL endemic regions could improve local health management.

Enhancing help-seeking behaviour among men who have sex with men at risk for sexually transmitted infections: the syn.bas.in randomised controlled trial.

OBJECTIVES: Men who have sex with men (MSM) are at increased risk for STIs and mental disorders. Syndemic theory holds that psychosocial issues co-occur and interact, and thus increase sexual risk behaviour. Psychosocial issue identification, referral and management might reduce risk behaviour. METHODS: In the syndemic-based intervention study, an open-label randomised controlled trial, MSM were enrolled at the STI outpatient clinic of the Public Health Service of Amsterdam. We screened participants using validated questionnaires on the following problem domains: alcohol and substance use, sexual compulsivity, anxiety, depression, attention deficit hyperactivity disorder, alexithymia, intimate partner violence and childhood sexual abuse. Individuals were randomly assigned (1:1) to receive either tailored, face-to-face feedback and help-seeking advice on mental health screening, or no feedback and no help-seeking advice. Participants were followed trimonthly for a year. The primary outcomes were self-reported and confirmed help-seeking behaviour. RESULTS: We included 155 MSM: 76 in the intervention group and 79 in the control group. At inclusion, 128 participants (83.1%) scored positive in at least one problem domain. We found no significant differences in self-reported or confirmed help-seeking behaviour between the intervention and the control group: 41% vs 29% (p=0.14) and 28% vs 22% (p=0.44), respectively. There were also no differences in STI incidence and condomless anal sex acts between the two groups. CONCLUSION: Screening showed high prevalence of problems related to mental health and substance use, while tailored feedback, advice and referral did not significantly increase help-seeking behaviour. Other interventions are needed to tackle the high burden of mental disorders among MSM. TRIAL REGISTRATION NUMBER: NCT02859935.

Vector bionomics and vectorial capacity as emergent properties of mosquito behaviors and ecology.

Mosquitoes are important vectors for pathogens that infect humans and other vertebrate animals. Some aspects of adult mosquito behavior and mosquito ecology play an important role in determining the capacity of vector populations to transmit pathogens. Here, we re-examine factors affecting the transmission of pathogens by mosquitoes using a new approach. Unlike most previous models, this framework considers the behavioral states and state transitions of adult mosquitoes through a sequence of activity bouts. We developed a new framework for individual-based simulation models called MBITES (Mosquito Bout-based and Individual-based Transmission Ecology Simulator). In MBITES, it is possible to build models that simulate the behavior and ecology of adult mosquitoes in exquisite detail on complex resource landscapes generated by spatial point processes. We also developed an ordinary differential equation model which is the Kolmogorov forward equations for models developed in MBITES under a specific set of simplifying assumptions. While mosquito infection and pathogen development are one possible part of a mosquito's state, that is not our main focus. Using extensive simulation using some models developed in MBITES, we show that vectorial capacity can be understood as an emergent property of simple behavioral algorithms interacting with complex resource landscapes, and that relative density or sparsity of resources and the need to search can have profound consequences for mosquito populations' capacity to transmit pathogens.

What every dentist needs to know about human papillomavirus.

Human papillomavirus (HPV) has a nearly ubiquitous prevalence within the adolescent and adult populations worldwide. The virus has been implicated for decades in cervical and uterine cancers, but recent data have shown an increase in cases of virally related oropharyngeal squamous cell carcinoma in both male and female cohorts. The objective of this article is to review the oral health implications of HPV infection, including oral and oropharyngeal prevalence, manifestations, neoplastic potential of HPV-associated head and neck lesions, treatment modalities, and vaccine use. The article will also discuss the continuing education needs of oral healthcare providers. Dental professionals should routinely screen patients for oral and oropharyngeal manifestations of HPV infection, seek timely referral for therapeutic intervention of potentially malignant lesions, and become strong proponents of HPV vaccinations for at-risk patients.

Clinical presentation of COVID-19-positive and -negative patients in Lagos Nigeria: A comparative study.

BACKGROUND: A lot has been documented about the pathophysiology and clinical presentation of coronavirus disease 2019 (COVID-19). We compared the clinical features of real-time reverse transcriptase polymerase-chain-reaction (RT-PCR) confirmed COVID-19 positive and negative patients admitted in Lagos State. METHODS: Medical records of all patients admitted in 15 isolation centres across Lagos state between 27th February 2020 and 30th September 2020, were abstracted and reviewed. We compared the clinical features, co-morbidities and clinical outcomes of COVID-19 positive and negative patients. RESULTS: A total of 3157 records of patients admitted in 15 isolation centres in Lagos State were reviewed of which 302 (9.6%) tested negative to RT-PCR COVID-19. There was no gender difference between COVID-19 positive and negative patients (P = 0.687). The average age of the negative patients was higher (46.8 ± 18.3 years) than positive patients (41.9 ± 15.5 years) (P < 0.001). A higher proportion of the COVID-19 negative patients had co-morbidity (38.1% vs. 27.8%), were symptomatic (67.5% vs. 44.6%) and higher mortality (21.9% vs. 6.6%) than positive patients (P < 0.001). The percentages with hypertension (26.2% vs. 21.0%, P = 0.038), diabetes (17.2% vs. 9.4%, P < 0.001), cardiovascular disease (2.3% vs. 0.9%, P < 0.029) and cancer (2.3% vs. 0.5%, P < 0.002) were more among patients without COVID-19. More patients without COVID-19 presented with fever (36.1% vs. 18.8%), cough (33.7% vs. 23.1%) and breathlessness (40.8% vs. 16.1%) than the positive patients (P < 0.001). CONCLUSION: Anosmia and dysgeusia were strongly associated with COVID-19. Clinical decision-making should only be used to prioritise testing and isolation of patients suspected to have COVID-19, especially in settings with limited access to diagnostic kits.

High incidence of HCV in HIV-negative men who have sex with men using pre-exposure prophylaxis.

BACKGROUND & AIMS: HCV has emerged as a sexually transmitted infection (STI) among HIV-positive men who have sex with men (MSM). We evaluated HCV incidence and its risk factors among HIV-negative MSM using HIV pre-exposure prophylaxis (PrEP). METHODS: Participants of the Amsterdam PrEP project were tested for HCV antibodies or HCV-RNA every 6 months. Participants used daily or event-driven PrEP and could switch regimens during follow-up. We calculated incidence rates (IRs) for overall HCV infection and separately for primary and re-infection. A univariable Bayesian exponential survival model was used to identify risk factors associated with incident HCV infection. The HCV NS5B gene fragment (709 bp) was sequenced and compared to HCV isolates from HIV-positive MSM and other risk groups (n = 419) using phylogenetic analysis. RESULTS: Among 350 participants contributing 653.6 person-years (PYs), we detected 15 HCV infections in 14 participants (IR = 2.30/100PY). There were 8 primary infections (IR = 1.27/100PY) and 7 re-infections (IR = 27.8/100PY). IR was 2.71/100PY in daily and 1.15/100PY in event-driven PrEP users. Factors associated with incident HCV infection were higher number of receptive condomless anal sex acts with casual partners (posterior hazard ratio [HR] 1.57 per ln increase; 95% credibility interval [CrI] 1.09-2.20), anal STI (posterior HR 2.93; 95% CrI 1.24-7.13), injecting drug use (posterior HR 4.69; 95% CrI 1.61-12.09) and sharing straws when snorting drugs (posterior HR 2.62; 95% CrI 1.09-6.02). We identified robust MSM-specific HCV clusters of subtypes 1a, 4d, 2b and 3a, which included MSM with and without HIV. CONCLUSIONS: HIV-negative MSM using PrEP are at risk of incident HCV infection, while identified risk factors are similar to those in HIV-positive MSM. Regular HCV testing is needed, especially for those with a previous HCV infection and those reporting risk factors. LAY SUMMARY: We report that hepatitis C virus infections are frequently acquired among HIV-negative men who have sex with men (MSM) using pre-exposure prophylaxis to prevent HIV infection. New infections occurred more frequently in those reporting receptive anal sex without using condoms, having an anal sexually transmitted infection, injecting drugs, and sharing straws when snorting drugs. The viruses found in HIV-negative men using pre-exposure prophylaxis are genetically similar to those in HIV-positive men, but not in other hepatitis C risk groups, suggesting that (sexual) transmission is occurring between HIV-positive MSM and HIV-negative MSM using pre-exposure prophylaxis. CLINICAL TRIAL NUMBER: Dutch trial registration number NTR5411.

A hybrid model for the effects of treatment and demography on malaria superinfection.

As standard mathematical models for the transmission of vector-borne pathogens with weak or no apparent sterilizing immunity, Susceptible-Infected-Susceptible (SIS) systems such as the Ross-Macdonald equations are a useful starting point for modeling the impacts of interventions on prevalence for diseases that cannot superinfect their hosts. In particular, they are parameterizable from quantities we can estimate such as the force of infection (FOI), the rate of natural recovery from a single infection, the treatment rate, and the rate of demographic turnover. However, malaria parasites can superinfect their host which has the effect of increasing the duration of infection before total recovery. Queueing theory has been applied to capture this behavior, but a problem with current queueing models is the exclusion of factors such as demographic turnover and treatment. These factors in particular can affect the entire shape of the distribution of the multiplicity of infection (MOI) generated by the superinfection process, its transient dynamics, and the population mean recovery rate. Here we show the distribution of MOI can be described by an alternative hyper-Poisson distribution. We then couple our resulting equations to a simple vector transmission model, extending previous Ross-Macdonald theory.

An 5 GABAA Receptor Inverse Agonist, 5IA, Attenuates Amyloid Beta-Induced Neuronal Death in Mouse Hippocampal Cultures.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder for which no cognition-restoring therapies exist. Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the brain. Increasing evidence suggests a remodeling of the GABAergic system in AD, which might represent an important therapeutic target. An inverse agonist of 5 subunit-containing GABAA receptors (α5GABAARs), 3-(5-Methylisoxazol-3-yl)-6-[(1-methyl-1,2,3-triazol-4-yl)methyloxy]-1,2,4-triazolo[3-a]phthalazine (5IA) has cognition-enhancing properties. This study aimed to characterize the effects of 5IA on amyloid beta (A1-42)-induced molecular and cellular changes. Mouse primary hippocampal cultures were exposed to either A1-42 alone, or 5IA alone, 5IA with A1-42 or vehicle alone, and changes in cell viability and mRNA expression of several GABAergic signaling components were assessed. Treatment with 100 nM of 5IA reduced A1-42-induced cell loss by 23.8% (p < 0.0001) after 6 h and by 17.3% after 5 days of treatment (p < 0.0001). Furthermore, we observed an A1-42-induced increase in ambient GABA levels, as well as upregulated mRNA expression of the GABAAR α2,α5,2/3 subunits and the GABABR R1 and R2 subunits. Such changes in GABARs expression could potentially disrupt inhibitory neurotransmission and normal network activity. Treatment with 5IA restored A1-42-induced changes in the expression of α5GABAARs. In summary, this compound might hold neuroprotective potential and represent a new therapeutic avenue for AD.

What every dentist needs to know about obstructive sleep apnea.

Sleep apnea has 2 variants that are classified by their etiologic mechanism, namely, an obstructive or a central origin. Despite the clinical and scientific advancements in obstructive sleep apnea (OSA) over the past 20 years, a majority of affected patients remain undiagnosed. This article reviews aspects of unmanaged OSA, including the oral and maxillofacial signs and symptoms, systemic risk factors, diagnostic criteria, guidelines for patient referral to a sleep physician, and clinical management techniques. Additionally, the role of dentists in oral appliance therapy is explored.